Power conversion apparatuses (power converters) are typically used in converting high-level and unregulated input voltages (e.g., high voltages) into output voltages with low levels (e.g., low voltages) and good stability that are suitable for use in various types of electronic devices. Accordingly, such power conversion apparatuses are widely applicable for implementation in electronic devices, such as computers, office automation equipment, industrial control equipment and communication instruments.
Such power converters can include a control circuit, which can be implemented as an integrated circuit (IC) chip, a transformer, and can also include other circuit elements (e.g., resistors and capacitors). The control circuit of a given power converter can adjust a current of a primary-side winding of the transformer using a pulse width modulation (PWM) signal and a switch unit, so as to regulate an output voltage of the power converter. The control circuit can further detect an input voltage and the output voltage, determine their relationship to one another, and then adjust the PWM signal appropriately to achieve a desired correspondence between the input voltage and the output voltage. In some instances, it can be desirable for a control chip of a power converter to include or perform additional functions. However, adding such additional functionality can increase the complexity and/or size (e.g., package size) of a corresponding control chip, which can be undesirable from a design and/or manufacturing cost standpoint.